THE MAJOR EXCRETORY SECRETORY PROTEASE FROM LUCILIA-CUPRINA LARVAE ISALSO A GUT DIGESTIVE PROTEASE/

The major excretory/secretory protease from Lucilia cuprina larvae is also a gut digestive protease. International Journal for Parasitology 26: 623-628. The larvae of the By Lucilia cuprina excrete or secrete a chymotrypsin (LCTb) onto the skin of sheep to facilitate the establis hment of the larval infestation. A combination of immunoblotting and R T-PCR approaches has established that this protease is also a gut dige stive protease. LCTb is synthesized primarily in the cardia, a small h ighly specialized organ located at the anterior end of the midgut and by midgut cells. There is also some expression by the hindgut but no e xpression by salivary glands. Excretion of LCTb with waste products or regurgitation of the gut contents of the larvae may explain how this protease Is transferred from the larval gut onto ovine skin. LCTb is f irst expressed in eggs and constitutively expressed throughout each la rval instar, but is not expressed in pupae or adult flies. It is concl uded that LCTb could be involved in the establishment of larvae on she ep skin as well as acting as a general gut digestive enzyme. Copyright (C) 1996 Australian Society for Parasitology. Published by Elsevier S cience Ltd.